Aircraft: CHALLENGER CL604
Phase of flight: Parked
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown

Near the end of a five leg; sixteen hour duty day that ended at shortly before dawn; I MEL'ed four cabin items. Three of the items were passenger convenience items covered by MEL 25-60-3. Item number three of four was covered by MEL 25-20-1-2. Leg three was supposed to be our last. Prior to leg two I was notified that operations was unable to contact the FBO at our final destination where we were to arrive around midnight with passengers. Prior to leg three we still did not know if the FBO at our destination was going to be open. We contacted Operations while in flight on our way to that destination and was told that the FBO would be closed and would we be willing to reposition the airplane to help in the recovery of an international flight later that morning. It would put us right at sixteen hours duty time. I conferred with the rest of the crew and we decided to position the plane. Because the FBO was closed we did not have enough fuel to make a flight non-stop to the reposition destination so operations had us stop for fuel. I felt somewhat tired on the last leg into our final destination but a cup of coffee helped maintain my alertness at a satisfactory level. After landing my mind and body started relaxing and I filled out the flight log and was made aware of some items in the cabin that were broken/inoperative so I wrote them up and contacted Maintenance with the MEL book on the dash of the airplane. Maintenance gave me the information needed to fill out the sheet at the front of the MEL book and I did not have my MEL copy opened to the offending MEL as I had another MEL to fill in after it. My plan was to review the MEL book when I finished filling in the MEL sheet and I did look at 25-60-3; but failed to look at 25-20-1-2. I am not sure why I missed this very important step; but I did. It may have been the unwinding effect of finishing up a sixteen hour day. It might have been the time of day. It might have been the pressure to close out our duty day before our normal one hour duty on the ground. It probably was a bit of the three. I believe I have a reputation for striving to be as compliant with the SOP's; FAR's; and Operation Spec's as any pilot at this carrier and the one time I missed looking at one single MEL it was the one that I needed to really look at as it was a (M) maintenance required item. I would not have allowed the aircraft to remain in a 'B' status had I done what I always had done previously. I flew home the next day. To avoid a recurrence of this event I will never again accept any duty over fourteen hours and when I find myself getting tired I will greatly slow my 'Professional Pace' to accommodate any possible reduced alertness. I have always looked at each MEL that is open on an aircraft that I accept and each that I write up so I will redouble my efforts to continue to do so. A CL604 Captain failed to note a MEL item that he entered in the maintenance log at the end of a sixteen hour day required maintenance attention before the next flight.